HW very hot, no CH, boiler firing randomly - no idea!

[Steve82]

Hi

Sorry if this is a bit long winded, but I was wondering if anyone could help with some issues I’m having with my central heating system I’d be very grateful

We have a boiler downstairs (Ideal Classic, ACL Lifestyle LP722 programmer, room stat, TRV’s on all radiators) which heats a cylinder in the loft. There is also an ACL Lifestyle Mid-position valve, a cylinder stat, immersion heater (switched off) and a pump for the central heating up there.

We noticed some time ago that the water coming from the hot tap suddenly increased in temperature. This was back in April when we were still heating (set for hour in the morning, 3 hours in the evening) and at the time, the hot water was set for 1 hour in the morning and 2 in the evening.

Once we stopped heating (but still using the hot water), we noticed that the boiler would fire randomly throughout the day for short periods. We tried killing the mains supply to the boiler to re-set the programmer but it made no difference.

When I set both the heating and hot water to ‘off’ on the programmer, the hot water remains hot (we never run out), so the boiler firing during the day is keeping it hot. Every time I have been in the loft the mid-position valve has been sat to ‘W’ and when I try and move it, it ‘pings’ straight back to ‘W’.

Today I put both the heating and hot water on. The Mid-position valve stays at ‘w’ and the pump doesn’t kick in, or even turn over. The radiators have not got warm.

Other info:

- I’ve noticed that the water in the heating header tank is warm. It is not overflowing but there is a lot of sludge at the bottom of the tank.
- Cylinder stat is set to 50 degrees and is securely strapped to the boiler in a cut out in the cylinder insulation
- No work has been carried out to the boiler to coincide with any of the issues described above

Thanks in advance for any help you can give – pulling my hair out!

Steve

 

[Phill Peck]

Un clip the motor head from the 3 port valve.

See if the spindle on the valve is moving freely.

 

[Steve82]

Thanks gasservice1985, having to go to NI for work last minute but will check and report back on Thurs when I get back.

 

[Steve82]

Un clip the motor head from the 3 port valve.

See if the spindle on the valve is moving freely.

Took the motor out and the spindle moves freely.

To do this I obviously cut the power to the valve, pump, boiler and immersion in the loft as well as the programmer which is downstairs with the boiler.

When I switched everything back on, I turned the hot water on (on its own) at the programmer - the valve indicator clicked to 'W'. I then turned on the hot water and heating together and the valve clicked to 'H'. When I switched it to just heating, it remained on 'H', when I selected just hot water again, it remains on 'H'.

It's worth mentioning that the micro-switch in the valve head clicks with every movement (as it should I'm guessing).

Any help gratefully received!